WO2001011208A1

WO2001011208A1 - Internal combustion engine comprising a secondary air injection system

Info

Publication number: WO2001011208A1
Application number: PCT/EP2000/007738
Authority: WO
Inventors: Holger Paffrath; Karl Ernst Hummel; Georg Knoch; Thomas Butz; Günter ZIRNIG
Original assignee: Filterwerk Mann+Hummel Gmbh
Priority date: 1999-08-10
Filing date: 2000-08-09
Publication date: 2001-02-15
Also published as: EP1203142B1; DE19937781A1; ATE264993T1; EP1203142A1; DE50006172D1

Abstract

The invention relates to an internal combustion engine comprising at least one line system for secondary air. A module body comprises a portion of the lines (25, 30, 35), a portion of the actuating valves (26a, 31, 26b), and check valves (27). The throttle valve (13) and its actuator (36) are additionally integrated in said module. A line section (14) which is part of the intake system (11) is also integrated in the module. The admissions of the lines (35, 30) are easily realized in said line section. The line (30) is intended for recirculating exhaust gas. It is also possible to partially realize the depicted idea with regard to integration. It is also possible to simultaneously utilize the supply line (29) in the exhaust (21) of the internal combustion engine as a bleed line for the exhaust gas. All of these measures are suited for reducing the installation space and the number of components for the internal combustion engine, whereby they yield very economical solutions.

Description

Internal combustion engine with secondary air injection system

description

State of the art

The invention relates to an internal combustion engine, which has a line system for secondary air for introduction into the exhaust tract, according to the preamble of claim 1. According to the preamble of claim 12, the internal combustion engine can additionally contain a line system for exhaust gas recirculation. In addition, the invention relates to a line module for integration into the internal combustion engine according to the preamble of claim 13.

Secondary air intake systems are used to reduce HC and CO during the cold start of internal combustion engines. With these systems, fresh air is blown onto the exhaust gas side and thus post-oxidation of HC and CO is achieved. At the same time, the exhaust gas temperature increases and the catalytic converter starts earlier.

Such a secondary air intake system is e.g. B. from WO 97/38212. The basic structure can be seen in Figure 2. The secondary air is withdrawn through a line 13 from the intake tract of the internal combustion engine on the clean side in front of a throttle valve 33 and pumped through a line 26 into the exhaust area 31. Various valves can be used to control the system. According to FIG. 3, the compressor 26 can be driven by a turbine 35, which takes advantage of the pressure difference that is established in the intake manifold by the throttle valve 33.

On the other hand, exhaust gas recirculation systems are used especially in the partial load range of the internal combustion engine, which lead to a reduction of NO _x . Such a ches system can be z. B. EP 596 855 A1. According to FIG. 1 of this document, exhaust gas is introduced into the intake tract 14 of an internal combustion engine 1 through a valve 19 and mixes with the intake air. This return reduces the combustion temperature and thus reduces the formation of nitrogen oxides. These systems are also implemented using pipes, valves and connecting elements.

The lines for secondary air and exhaust gas recirculation can be integrated in the cylinder head. This idea is e.g. B. proposed in US 4,267,812. The cylinder head can be designed as a one-part or multi-part casting, the channels being formed by the casting mold. This can save space for the air duct systems. Weight reduction can also be achieved. To a certain extent, the assembly effort for the piping system is still eliminated, at least for the areas integrated in the cylinder head.

The valves, compressors and control devices required for the air duct systems cannot, however, be easily integrated into the cylinder head. This area of the internal combustion engine is already extremely complex, since assemblies of different functions have to be accommodated in a small space. In particular, the intake and exhaust valves for the cylinders, their control and drive are to be accommodated there. Sufficient oil lubrication must be ensured for these mechanical parts. Oil separation and cylinder head cooling are also housed in this engine area. Therefore, the control and regulation for secondary air or exhaust gas recirculation systems is housed in line sections that lie outside the cylinder head and ensure a connection from this to the intake manifold area in front of the throttle valve or the exhaust system. Here, however, there is an increased assembly and production effort. The individual components can sometimes only be attached during final assembly of the internal combustion engine or even only when the engine is installed in the engine compartment. This also increases the risk of errors in assembly increased. These economic aspects allow the described line systems to be used only in middle and upper class vehicles. However, the increasing demands on the exhaust gas values of internal combustion engines are increasing the interest in finding an economical solution for improving the exhaust gas values.

The object of the invention is therefore to create a line system for an internal combustion engine for secondary air injection and / or exhaust gas recirculation, which is inexpensive to manufacture and reliable in operation. This object is achieved by the features of claims 1 and 12. Furthermore, a line module is claimed according to claim 13, which is suitable for installation in an internal combustion engine.

Advantages of the invention

The internal combustion engine according to the invention has at least one line system for secondary air, which is constructed as already described. A module is attached to the internal combustion engine, which combines at least one compressor duct with a connection for each supply line, a connection for a compressor and a line section of the intake tract. Because the line section is integrated in the module, it can be attached to the intake manifold in such a way that the air is passed from the intake line of the intake tract through the line section into the intake pipe. An arrangement of the module in other sections of the intake tract is of course also conceivable.

A compressor can either extract secondary air from the intake tract, especially behind the air filter, or from another location in the engine compartment. This is attached to the compressor connection, whereby the air is pumped into the module. Hydrodynamic flow machines, but also all other types of pumping, which can be driven by an electric motor, for example, can be used as compressors. The air passes through from the compressor connection a compressor channel and exits the module through the connector to enter the supply line leading to the exhaust. Exhaust in the broadest sense means the entire exhaust tract for the combustion gases, starting with the cylinder outlets. If the cylinders are divided into several cylinder banks, several supply lines can also be provided on the internal combustion engine. The compressor channel can then branch within the module, which saves the connection effort for pipe switches and has one connection per supply line.

Using the module described has several advantages. On the one hand, the direct connection to the intake manifold or to the engine block of the internal combustion engine, in particular the cylinder head, results in an extremely compact design. This not only saves installation space but also shortens the cable routes. As a result, the flow resistance of the line system can be reduced, especially since the compressor channels can be optimized in terms of flow. The streamlined design of the lines leads to shorter response times of the system and thus to an improved function of the internal combustion engine. The module can be used as a pre-assembled unit. B. can be supplied by a system supplier for final assembly of the internal combustion engine. This avoids possible errors that can occur during final assembly. In addition, a higher level of efficiency in the manufacture of the internal combustion engine can be achieved through a favorable division of labor. The module can even be attached to the intake manifold before delivery. Another option is to design the module as an integral part of the intake manifold. Part of the channel structures and connections can then be formed by the housing parts of the intake manifold and can be supplemented, for example, by a cover.

The supply lines of the internal combustion engine can be integrated in the cylinder head. In this case, a connection or integration of the module to both the intake manifold and the cylinder head is necessary. As a result, the internal combustion engine can be made even more compact. The supply lines Ren to the exhaust of the internal combustion engine. In this context, exhaust means the entire exhaust route of the combustion gases from the cylinder heads. The secondary air is advantageously introduced upstream of the catalytic converter in order to improve its behavior in the cold start phase.

According to a further embodiment of the invention, the compressor connection can be designed such that the compressor can be at least partially integrated into the module. In particular, if the compressor is a hydrodynamic fluid flow machine, the housing shell for its impeller can be designed as part of the module. This saves the production of the corresponding housing shells on the compressor. If the module is designed as a cast part, there is no additional manufacturing effort. The module can be made of plastic or light metal, e.g. Aluminum.

In the event that the compressor is driven by a turbine that uses the combustion air in the intake tract to drive, a particularly favorable embodiment of the invention results from the fact that a turbine duct is integrated into the module, which opens into the line section of the intake manifold. The other end of the turbine duct is formed by a turbine connection, which ensures that the drive air of the turbine is discharged and that it is mounted on the module. In addition, a supply line from the intake tract (in front of the throttle valve) to the turbine can be integrated into the module. As a result, the idea of integration according to the invention is driven further.

Advantageously, the turbine at the turbine connection can be partially integrated into the module in the manner already described for the compressor. By appropriate design of the housing shells of the module, the entire turbine compressor unit can even be integrated into the module. A particularly high level of component integration can be achieved in this way. Another variant of the invention results if the control valves for the secondary air quantity are at least partially integrated into the module. Corresponding connections can be provided for this in the module, whereby the component expenditure for the secondary air system can be further reduced. In particular, module valve seats can be provided, and commercially available valve bodies can be attached to the module. The check valves necessary in the feed line can also advantageously be used. Accordingly, these can be partially integrated in the feed line and partially in the module or even entirely in the module. Furthermore, a control valve for the turbines may be necessary, which can also be integrated into the module in the manner described. The control valve for the turbine is also necessary in the broader sense for controlling the amount of secondary air. The control valves can be designed as switching valves (positions open and closed) and as stepless valves. The infinitely variable design is advantageous because it allows the secondary air volume to be metered optimally for each operating state of the internal combustion engine.

In the event that an exhaust gas recirculation is also provided for the internal combustion engine, according to a modification of the invention, an exhaust gas duct can also be integrated into the module, which ensures the supply of the exhaust gases into the line section of the module. Here, too, there is no need for the connection. In addition, the necessary recirculation valve for the exhaust gas can advantageously be at least partially integrated into the module.

The integration of the throttle valve in the line section of the module is particularly advantageous. In particular, if the throttle valve itself is designed as a module, it can easily be attached to the connection of the module to the intake manifold or to the intake tract in front of the intake manifold. This arrangement is also advantageous for the introduction of the exhaust gases, since thorough mixing with the intake air is achieved. The confluence of the exhaust duct in the line section can be cost-effective from the point of view of the flow mechanics with regard to an optimal mixing of the exhaust gas with the intake air.

Particularly advantageous is an arrangement in which the throttle valve is attached to one side of the module, the exhaust duct and the turbine duct are fed to the module in the subsequent line section and the collecting space of the intake manifold begins at the other end of the line section.

The various configurations of the invention all follow the greatest possible integration concept for the module. The advantages described for the claim have an effect the more the degree of integration for the module described is chosen. Therefore, the production of the module as part of the intake manifold housing is the optimal solution.

Irrespective of the module, however, the concept of integration can also be implemented directly on the internal combustion engine according to a further embodiment of the invention. This is achieved in that the exhaust gas recirculation is at least partially formed by the supply line which is provided for the secondary air line. This makes it possible to save on pipeline routes, with the common section of the piping systems being used either for extracting exhaust gas from the exhaust or for feeding secondary air into the exhaust. This design variant takes advantage of the fact that the operating states of the internal combustion engine never occur at the same time with exhaust gas recirculation or secondary air injection. This design of the invention leads to a saving of pipeline routes with the advantages of space and component savings already described, according to the task.

A module for an internal combustion engine is suitable for being installed in the arrangements of the internal combustion engine described. ES has the features according to the invention. The module can also be formed at least partially by the intake manifold housing. This further supports the idea of integration. For example, connections between module and intake manifold housing can be saved. Ideally, the entire module is part of the intake manifold housing. The housing structure of the intake manifold can then be manufactured as a whole. Manufacturing steps for the production of an additional module are therefore eliminated. These and further features of preferred developments of the invention are evident from the claims and also from the description and the drawings, the individual features being implemented individually or in groups in the form of subcombinations in the embodiment of the invention and in other fields, and can represent advantageous and protectable versions for which protection is claimed here.

drawing

Further details of the invention are described in the drawings using schematic exemplary embodiments. Show here

1 shows the block diagram of an internal combustion engine with an intake tract and

Exhaust, where possible system limits of the module are indicated,

Figure 2 is a three-dimensional view of the module attached to the

Intake pipe of an internal combustion engine with a V-shaped cylinder arrangement,

Figure 3 shows the base part of the module in the three-dimensional view from

Seen suction pipe,

4 shows the base part according to FIG. 3 in a three-dimensional view from the throttle valve and 5 shows a variant of detail X according to FIG. 4 with installation space for one

Turbine blade.

Description of the embodiments

Due to the schematically illustrated internal combustion engine according to FIG. 1, the combustion air takes the following route, indicated by double arrows. It enters an intake tract 11 through an intake port 10, passes through an air filter 12, passes a throttle valve 13, is led through a line section 14 in a module 15 into a collecting space 16 of an intake manifold 17, passes through intake ducts 18 into a cylinder head 19, and becomes in cylinders 20 burned and exits the internal combustion engine 21. Furthermore, the internal combustion engine is equipped with a line system for secondary air injection and for exhaust gas recirculation. The air flows in this line system are identified by simple arrows. For secondary air intake, intake air is taken from the intake tract 11 and fed to a compressor 23 through an extraction line 22. This has a compressor connection 24 through which the secondary air is fed into a compressor duct 25. There it passes a control valve 26a and a check valve 27 and enters through a further connection 28 into a feed line 29 which opens into the exhaust 21.

The feed line 29 is used at the same time for the exhaust gas removal. The exhaust gas enters the module 15 through the connection 28, the check valve 27 preventing a return line to the compressor. However, an exhaust gas duct 30 branches off from the compressor duct 25, which allows the exhaust gas to be introduced into the line section 14 shortly behind the throttle valve 13. A recirculation valve 31 is provided to control the exhaust gas flow. The compressor 23 is driven by a turbine 32. This uses the pressure difference in the intake tract 11 caused by the throttle valve 13, in which it draws intake air through a supply line 33 in front of the throttle valve, which leads via a turbine connection 34 into a turbine duct 35, which is part of the module 15 and into the line section 14 behind the throttle valve 13 opens into the intake tract 11. A control valve 26b is provided in the turbine duct. The throttle valve 13 has an actuator 36 for stepless adjustment.

FIG. 2 shows a schematic representation of the spatial arrangement of all components involved in the internal combustion engine according to FIG. 1. This example shows an engine block 37 with a v-shaped arrangement of the cylinders on two cylinder banks 38. The individual components are identified by the reference numerals corresponding to FIG. 1 and are therefore not described again. However, the following peculiarities arise due to the geometric arrangement.

The feed line 29 cannot be seen since it is integrated in the cylinder head. There is a supply line for each cylinder bank 38, these being accessible via inlet openings 39 on the cylinder head. The module with the connections 28 is fastened to these input openings. The module 15 is constructed in the form of a disk. It is flanged to the end of the suction pipe, the line section 14 opening into an inlet 40 in the collecting space of the suction pipe. On the other side of the line section 14, the throttle valve is fastened to a receptacle 41.

Alternatively (not shown), the module can be designed as an integral part of the intake manifold. This eliminates the need for a flange connection between the module and the intake manifold. Instead of the disc-shaped structure, the integrated module can be produced, for example, together with the suction tube using the lost-core technique. The branching of the exhaust duct 30 from the compressor duct takes place outside the module body. The return valve 31 is attached to the visible section of the exhaust gas duct 30 and leads into the base body 42. There is a second section of the exhaust duct 31, which is not visible in FIG. 2.

A possible construction of the base body 42 for the module can be seen in FIGS. 3 and 4. The two sides of the base body can be seen, both being provided with end plates, so that closed channel structures are formed. Alternatively, the base body could be designed as part of the intake manifold housing, as a result of which one of the end plates would be omitted. The channel sections located in the module are provided with the reference symbols corresponding to FIG. 1 and are not to be described in more detail. However, there are the following special features.

First of all, the extremely short line section 14 is striking. This is no longer than the base body 42 is thick. In this short section, both the turbine duct 35 and the exhaust duct 30 can be supplied. As described for FIG. 2, the throttle valve can also be attached to the base body. This extends the line section by the amount of the thickness of the throttle valve module. The throttle valve can be seen as part of the module.

The base body 42 has various valve connections 43a to 43d. These are valve connections 43a for the check valves 27, a valve connection 43b for the return valve 31, a valve connection 43c for the control valve 26a and a valve connection 43d for the control valve 26b. The valve connection 43b and the turbine connection 34 and the compressor connection 24 are designed as openings in the end plate (not shown) of the base body 42 and are therefore only represented by dashed circles. Valve seats 44 are also provided in the base body 42 for the control valves 26a, b. This enables a partial integration of these valves in the base body. The valve seats interact with the valve disks of the control valves 26a, b, not shown, which are inserted into the base body by the receptacles 43c, d.

FIG. 5 shows an alternative embodiment of the main body 42. The turbine connection 34a is designed in such a way that the impeller of the turbine can extend into the main body 42. This saves a housing shell of the turbine. The turbine connection 34a is funnel-shaped in accordance with the outer contours of the turbine wheel, not shown. It opens directly into the turbine duct 35. A corresponding connecting duct 45 is shown in dashed lines.

Claims

claims

1. internal combustion engine, which

- an engine block (37) with a cylinder head (19),

- An intake tract (11) for the combustion air with a suction pipe (17) and

- An exhaust (21), with a pipe system for secondary air, which

- A sampling line (22) for secondary air from the intake tract

- A compressor (23) for the secondary air and starting from this

- Has at least one supply line (29) for the secondary air in the exhaust pipe (21), characterized in that at least one compressor duct (25) with a connection (28) for each supply line (29), a compressor connection (24) and a line section ( 14) of the intake tract are combined in a module (15).

2. Internal combustion engine according to claim 1, characterized in that the

Compressor (23) is at least partially integrated in the module (15) at the compressor connection (24).

3. Internal combustion engine according to one of the preceding claims, wherein the compressor is connected to a turbine (32) which for driving through the combustion air with a before a throttle valve (13) in the intake tract (11) opening supply line (33) and one after Throttle valve (13) is provided in the discharge line opening into the intake tract (11), characterized in that the discharge line is formed by a turbine duct (35) which is integrated in the module (15), opens into the line section (14) and has a turbine connection (34, 34a) for the turbine (32).

4. Internal combustion engine according to claim 3, characterized in that the feed line (33) is integrated in the module.

5. Internal combustion engine according to claim 3, characterized in that the turbine (32) at the turbine connection (34, 34a) is at least partially integrated in the module (15).

6. Internal combustion engine according to one of the preceding claims, wherein at least one control valve (26a, 26b) is provided for controlling the amount of secondary air, characterized in that it is at least partially integrated into the module.

7. Internal combustion engine according to one of the preceding claims, wherein at least one check valve (27) is provided for the feed line (29), characterized in that it is at least partially integrated into the module.

8. Internal combustion engine according to one of the preceding claims, which has an exhaust gas recirculation (29, 30, 31) with a recirculation valve (31), characterized in that the exhaust gas recirculation is partially formed by an exhaust gas duct (30) which in the module (15th ) is integrated and opens into the line section (14).

9. Internal combustion engine according to claim 7, characterized in that the

Return valve (31) is at least partially integrated in the module.

10. Internal combustion engine according to one of the preceding claims, characterized in that a receptacle (41) for the throttle valve (13) is provided on the line section (14).

11. Internal combustion engine according to one of the preceding claims, characterized in that the module (15) is attached to it in such a way that the line section (14) opens into an inlet (40) of the intake manifold.

12. Internal combustion engine according to one of the preceding claims, characterized in that the module (15) is attached to it in such a way that the connection (28) of the compressor duct (25) into an inlet opening (39) of the supply line (29) integrated in the cylinder head. empties.

13. Internal combustion engine, according to one of the preceding claims, wherein the supply line is equipped with a valve, in particular a check valve (27), and a line system for exhaust gas recirculation, which, for control purposes, has a recirculation valve (31), characterized in that the exhaust gas recirculation is partially is formed by the feed line (29), the valve in the feed line and the return valve (31) being connected in parallel.

14. Module (15) for an internal combustion engine, characterized in that at least one compressor channel (25) for the secondary air introduction and a line section (14) for the conduction of combustion air are integrated therein, so that it is installed in an internal combustion engine according to one of the previous claims is suitable.

15. Intake pipe for an internal combustion engine, characterized in that the

Module (15) according to claim 13, at least partially formed by the intake manifold housing.